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;;;; stuff related to the toplevel read-eval-print loop, plus some
;;;; other miscellaneous functions that we don't have any better place
;;;; for
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB!IMPL")
;;;; magic specials initialized by GENESIS
;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..))
;;; of all static symbols in early-impl.lisp.
(defvar sb!vm::*current-catch-block*)
(defvar sb!vm::*current-unwind-protect-block*)
#!+hpux (defvar sb!vm::*c-lra*)
(defvar *free-interrupt-context-index*))
;;; specials initialized by !COLD-INIT
;;; FIXME: These could be converted to DEFVARs.
(declaim (special #!+(or x86 x86-64) *pseudo-atomic-bits*
#!+sb-thruption *thruption-pending*))
;;;; default initfiles
(defun sysinit-pathname ()
(or (let ((sbcl-homedir (sbcl-homedir-pathname)))
(when sbcl-homedir
(probe-file (merge-pathnames "sbclrc" sbcl-homedir))))
(merge-pathnames "sbcl\\sbclrc"
(defun userinit-pathname ()
(merge-pathnames ".sbclrc" (user-homedir-pathname)))
(defvar *sysinit-pathname-function* #'sysinit-pathname
"Designator for a function of zero arguments called to obtain a
pathname designator for the default sysinit file, or NIL. If the
function returns NIL, no sysinit file is used unless one has been
specified on the command-line.")
(defvar *userinit-pathname-function* #'userinit-pathname
"Designator for a function of zero arguments called to obtain a
pathname designator or a stream for the default userinit file, or NIL.
If the function returns NIL, no userinit file is used unless one has
been specified on the command-line.")
;;;; miscellaneous utilities for working with with TOPLEVEL
;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
;;; by QUIT) is caught and any final processing and return codes are
;;; handled appropriately.
(defmacro handling-end-of-the-world (&body body)
(catch '%end-of-the-world
(progn ,@body)
(defvar *exit-lock*)
(defvar *exit-in-process* nil)
(declaim (type (or null real) *exit-timeout*))
(defvar *exit-timeout* 60
"Default amount of seconds, if any, EXIT should wait for other
threads to finish after terminating them. Default value is 60. NIL
means to wait indefinitely.")
(defun os-exit-handler (condition)
(declare (ignore condition))
(os-exit *exit-in-process* :abort t))
(defvar *exit-error-handler* #'os-exit-handler)
(defun call-exit-hooks ()
(unless *exit-in-process*
(setf *exit-in-process* 0))
(handler-bind ((serious-condition *exit-error-handler*))
(call-hooks "exit" *exit-hooks* :on-error :warn)))
(defun %exit ()
;; If anything goes wrong, we will exit immediately and forcibly.
(handler-bind ((serious-condition *exit-error-handler*))
(let ((ok nil)
(code *exit-in-process*))
(if (consp code)
;; Another thread called EXIT, and passed the buck to us -- only
;; final call left to do.
(os-exit (car code) :abort nil)
(setf ok t))
(os-exit code :abort (not ok)))))))
;;;; miscellaneous external functions
(defun split-seconds-for-sleep (seconds)
(declare (muffle-conditions t))
(declare (optimize speed))
;; KLUDGE: This whole thing to avoid consing floats
(flet ((split-float ()
(let ((whole-seconds (truly-the fixnum (%unary-truncate seconds))))
(values whole-seconds
(truly-the (integer 0 #.(expt 10 9))
(%unary-truncate (* (- seconds (float whole-seconds))
(load-time-value 1f9 t))))))))
(declare (inline split-float))
(typecase seconds
((single-float 0f0 #.(float sb!xc:most-positive-fixnum 1f0))
((double-float 0d0 #.(float sb!xc:most-positive-fixnum 1d0))
(multiple-value-bind (quot rem) (truncate (numerator seconds)
(denominator seconds))
(values quot
(* rem
#.(if (sb!xc:typep 1000000000 'fixnum)
'(truncate 1000000000 (denominator seconds))
;; Can't truncate a bignum by a fixnum without consing
'(* 10 (truncate 100000000 (denominator seconds))))))))
(multiple-value-bind (sec frac)
(truncate seconds)
(values sec (truncate frac (load-time-value 1f-9 t))))))))
(defun sleep (seconds)
"This function causes execution to be suspended for SECONDS. SECONDS may be
any non-negative real number."
(declare (explicit-check))
(when (or (not (realp seconds))
(minusp seconds))
(error 'simple-type-error
:format-control "Invalid argument to SLEEP: ~S, ~
should be a non-negative real."
:format-arguments (list seconds)
:datum seconds
:expected-type '(real 0)))
#!-(and win32 (not sb-thread))
(multiple-value-bind (sec nsec)
(if (integerp seconds)
(values seconds 0)
(split-seconds-for-sleep seconds))
;; nanosleep() accepts time_t as the first argument, but on some platforms
;; it is restricted to 100 million seconds. Maybe someone can actually
;; have a reason to sleep for over 3 years?
(loop while (> sec (expt 10 8))
do (decf sec (expt 10 8))
(sb!unix:nanosleep (expt 10 8) 0))
(sb!unix:nanosleep sec nsec))
#!+(and win32 (not sb-thread))
(sb!win32:millisleep (truncate (* seconds 1000)))
;;;; the default toplevel function
(defvar / nil
"a list of all the values returned by the most recent top level EVAL")
(defvar // nil #!+sb-doc "the previous value of /")
(defvar /// nil #!+sb-doc "the previous value of //")
(defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
(defvar ** nil #!+sb-doc "the previous value of *")
(defvar *** nil #!+sb-doc "the previous value of **")
(defvar + nil #!+sb-doc "the value of the most recent top level READ")
(defvar ++ nil #!+sb-doc "the previous value of +")
(defvar +++ nil #!+sb-doc "the previous value of ++")
(defvar - nil #!+sb-doc "the form currently being evaluated")
(defun interactive-eval (form &key (eval #'eval))
"Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
+++, ++, +, ///, //, /, and -."
(setf - form)
(let ((results (multiple-value-list (funcall eval form))))
(setf /// //
// /
/ results
*** **
** *
* (car results)))
(setf +++ ++
++ +
+ -))
(unless (boundp '*)
;; The bogon returned an unbound marker.
;; FIXME: It would be safer to check every one of the values in RESULTS,
;; instead of just the first one.
(setf * nil)
(cerror "Go on with * set to NIL."
"EVAL returned an unbound marker."))
(values-list /))
;;; Flush anything waiting on one of the ANSI Common Lisp standard
;;; output streams before proceeding.
(defun flush-standard-output-streams ()
(let ((null (make-broadcast-stream)))
(dolist (name '(*debug-io*
;; 0. Pull out the underlying stream, so we know what it is.
;; 1. Handle errors on it. We're doing this on entry to
;; debugger, so we don't want recursive errors here.
;; 2. Rebind the stream symbol in case some poor sod sees
;; a broken stream here while running with *BREAK-ON-ERRORS*.
(let ((stream (stream-output-stream (symbol-value name))))
;; This is kind of crummy because it checks in globaldb for each
;; stream symbol whether it can be bound to a stream. The translator
;; for PROGV could skip ABOUT-TO-MODIFY-SYMBOL-VALUE based on
;; an aspect of a policy, but if users figure that out they could
;; do something horrible like rebind T and NIL.
(progv (list name) (list null)
(handler-bind ((stream-error
(lambda (c)
(when (eq stream (stream-error-stream c))
(go :next)))))
(force-output stream))))
(defun process-init-file (specified-pathname kind)
(multiple-value-bind (context default-function)
(ecase kind
(values "sysinit" *sysinit-pathname-function*))
(values "userinit" *userinit-pathname-function*)))
(if specified-pathname
(with-open-file (stream (parse-native-namestring specified-pathname)
:if-does-not-exist nil)
(if stream
(load-as-source stream :context context)
(cerror "Ignore missing init file"
"The specified ~A file ~A was not found."
context specified-pathname)))
(let ((default (funcall default-function)))
(when default
(with-open-file (stream (pathname default) :if-does-not-exist nil)
(when stream
(load-as-source stream :context context))))))))
(defun process-eval/load-options (options)
(/show0 "handling --eval and --load options")
(flet ((process-1 (cons)
(destructuring-bind (opt . value) cons
(ecase opt
(with-simple-restart (continue "Ignore runtime option --eval ~S."
(multiple-value-bind (expr pos) (read-from-string value)
(if (eq value (read-from-string value nil value :start pos))
(eval expr)
(error "Multiple expressions in --eval option: ~S"
(with-simple-restart (continue "Ignore runtime option --load ~S."
(load (native-pathname value))))
(with-simple-restart (abort "Skip rest of --eval and --load options.")
(dolist (option options)
(process-1 option)))))
(defun process-script (script)
(flet ((load-script (stream)
;; Scripts don't need to be stylish or fast, but silence is usually a
;; desirable quality...
(handler-bind (((or style-warning compiler-note) #'muffle-warning)
(stream-error (lambda (e)
;; Shell-style.
(when (member (stream-error-stream e)
(list *stdout* *stdin* *stderr*))
;; Let's not use the *TTY* for scripts, ok? Also, normally we use
;; synonym streams, but in order to have the broken pipe/eof error
;; handling right we want to bind them for scripts.
(let ((*terminal-io* (make-two-way-stream *stdin* *stdout*))
(*debug-io* (make-two-way-stream *stdin* *stderr*))
(*standard-input* *stdin*)
(*standard-output* *stdout*)
(*error-output* *stderr*))
(load stream :verbose nil :print nil)))))
(if (eq t script)
(load-script *stdin*)
(with-open-file (f (native-pathname script) :element-type :default)
(sb!fasl::maybe-skip-shebang-line f)
(load-script f))))))
;; Errors while processing the command line cause the system to EXIT,
;; instead of trying to go into the Lisp debugger, because trying to
;; go into the Lisp debugger would get into various annoying issues of
;; where we should go after the user tries to return from the
;; debugger.
(defun startup-error (control-string &rest args)
(format *error-output*
"fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
(exit :code 1))
;;; the default system top level function
(defun toplevel-init ()
(/show0 "entering TOPLEVEL-INIT")
(let ( ;; value of --sysinit option
(sysinit nil)
;; t if --no-sysinit option given
(no-sysinit nil)
;; value of --userinit option
(userinit nil)
;; t if --no-userinit option given
(no-userinit nil)
;; t if --disable-debugger option given
(disable-debugger nil)
;; list of (<kind> . <string>) conses representing --eval and --load
;; options. options. --eval options are stored as strings, so that
;; they can be passed to READ only after their predecessors have been
;; EVALed, so that things work when e.g. REQUIRE in one EVAL form
;; creates a package referred to in the next EVAL form. Storing the
;; original string also makes for easier debugging.
(reversed-options nil)
;; Has a --noprint option been seen?
(noprint nil)
;; Has a --script option been seen?
(script nil)
;; Quit after processing other options?
(finally-quit nil)
;; everything in *POSIX-ARGV* except for argv[0]=programname
(options (rest *posix-argv*)))
(declare (type list options))
(/show0 "done with outer LET in TOPLEVEL-INIT")
;; FIXME: There are lots of ways for errors to happen around here
;; (e.g. bad command line syntax, or READ-ERROR while trying to
;; READ an --eval string). Make sure that they're handled
;; reasonably.
;; Process command line options.
(loop while options do
(/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
(let ((option (first options)))
(flet ((pop-option ()
(if options
(pop options)
"unexpected end of command line options"))))
(cond ((string= option "--script")
(setf disable-debugger t
no-userinit t
no-sysinit t
script (if options (pop-option) t))
((string= option "--sysinit")
(if sysinit
(startup-error "multiple --sysinit options")
(setf sysinit (pop-option))))
((string= option "--no-sysinit")
(setf no-sysinit t))
((string= option "--userinit")
(if userinit
(startup-error "multiple --userinit options")
(setf userinit (pop-option))))
((string= option "--no-userinit")
(setf no-userinit t))
((string= option "--eval")
(push (cons :eval (pop-option)) reversed-options))
((string= option "--load")
(push (cons :load (pop-option)) reversed-options))
((string= option "--noprint")
(setf noprint t))
((string= option "--disable-debugger")
(setf disable-debugger t))
((string= option "--quit")
(setf finally-quit t))
((string= option "--non-interactive")
;; This option is short for --quit and --disable-debugger,
;; which are needed in combination for reliable non-
;; interactive startup.
(setf finally-quit t)
(setf disable-debugger t))
((string= option "--end-toplevel-options")
;; Anything we don't recognize as a toplevel
;; option must be the start of user-level
;; options.. except that if we encounter
;; "--end-toplevel-options" after we gave up
;; because we didn't recognize an option as a
;; toplevel option, then the option we gave up on
;; must have been an error. (E.g. in
;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
;; this test will let us detect that the string
;; "--eval(b)" is an error.)
(if (find "--end-toplevel-options" options
:test #'string=)
(startup-error "bad toplevel option: ~S"
(first options))
;; Delete all the options that we processed, so that only
;; user-level options are left visible to user code.
(when *posix-argv*
(setf (rest *posix-argv*) options))
;; Disable debugger before processing initialization files & co.
(when disable-debugger
;; Handle initialization files.
(/show0 "handling initialization files in TOPLEVEL-INIT")
;; This CATCH is needed for the debugger command TOPLEVEL to
;; work.
(catch 'toplevel-catcher
;; We wrap all the pre-REPL user/system customized startup
;; code in a restart.
;; (Why not wrap everything, even the stuff above, in this
;; restart? Errors above here are basically command line
;; or Unix environment errors, e.g. a missing file or a
;; typo on the Unix command line, and you don't need to
;; get into Lisp to debug them, you should just start over
;; and do it right at the Unix level. Errors below here
;; are generally errors in user Lisp code, and it might be
;; helpful to let the user reach the REPL in order to help
;; figure out what's going on.)
(unless no-sysinit
(process-init-file sysinit :system))
(unless no-userinit
(process-init-file userinit :user))
(when finally-quit
(push (list :quit) reversed-options))
(process-eval/load-options (nreverse reversed-options))
(when script
(process-script script)
(bug "PROCESS-SCRIPT returned")))
(abort ()
:report (lambda (s)
(if script
;; In case script calls (enable-debugger)!
"Abort script, exiting lisp."
"Skip to toplevel READ/EVAL/PRINT loop.")
(/show0 "CONTINUEing from pre-REPL RESTART-CASE")
(values)) ; (no-op, just fall through)
(exit ()
:report "Exit SBCL (calling #'EXIT, killing the process)."
:test (lambda (c) (declare (ignore c)) (not script))
(/show0 "falling through to EXIT from pre-REPL RESTART-CASE")
(exit :code 1))))
;; one more time for good measure, in case we fell out of the
;; RESTART-CASE above before one of the flushes in the ordinary
;; flow of control had a chance to operate
(/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
(toplevel-repl noprint)
;; (classic CMU CL error message: "You're certainly a clever child.":-)
(critically-unreachable "after TOPLEVEL-REPL")))
;;; hooks to support customized toplevels like ACL-style toplevel from
;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
(defvar *repl-read-form-fun* #'repl-read-form-fun
"A function of two stream arguments IN and OUT for the toplevel REPL to
call: Return the next Lisp form to evaluate (possibly handling other magic --
like ACL-style keyword commands -- which precede the next Lisp form). The OUT
stream is there to support magic which requires issuing new prompts.")
(defvar *repl-prompt-fun* #'repl-prompt-fun
"A function of one argument STREAM for the toplevel REPL to call: Prompt
the user for input.")
(defvar *repl-fun-generator* (constantly #'repl-fun)
"A function of no arguments returning a function of one argument NOPRINT
that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
*STANDARD-OUTPUT* are set up.")
;;; read-eval-print loop for the default system toplevel
(defun toplevel-repl (noprint)
(/show0 "entering TOPLEVEL-REPL")
(let ((* nil) (** nil) (*** nil)
(- nil)
(+ nil) (++ nil) (+++ nil)
(/// nil) (// nil) (/ nil))
(/show0 "about to funcall *REPL-FUN-GENERATOR*")
(let ((repl-fun (funcall *repl-fun-generator*)))
;; Each REPL in a multithreaded world should have bindings of
;; most CL specials (most critically *PACKAGE*).
(handler-bind ((step-condition 'invoke-stepper))
(/show0 "about to set up restarts in TOPLEVEL-REPL")
;; CLHS recommends that there should always be an
;; ABORT restart; we have this one here, and one per
;; debugger level.
(abort "~@<Exit debugger, returning to top level.~@:>")
(catch 'toplevel-catcher
;; In the event of a control-stack-exhausted-error, we
;; should have unwound enough stack by the time we get
;; here that this is now possible.
(funcall repl-fun noprint)
(critically-unreachable "after REPL")))))))))
;;; Our default REPL prompt is the minimal traditional one.
(defun repl-prompt-fun (stream)
(fresh-line stream)
(write-string "* " stream)) ; arbitrary but customary REPL prompt
;;; Our default form reader does relatively little magic, but does
;;; handle the Unix-style EOF-is-end-of-process convention.
(defun repl-read-form-fun (in out)
(declare (type stream in out) (ignore out))
;; KLUDGE: *READ-SUPPRESS* makes the REPL useless, and cannot be
;; recovered from -- flip it here.
(when *read-suppress*
(warn "Setting *READ-SUPPRESS* to NIL to restore toplevel usability.")
(setf *read-suppress* nil))
(let* ((eof-marker (cons nil nil))
(form (read in nil eof-marker)))
(if (eq form eof-marker)
(defun repl-fun (noprint)
(/show0 "entering REPL")
;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
(unless noprint
(funcall *repl-prompt-fun* *standard-output*)
;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
;; odd. But maybe there *is* a valid reason in some
;; circumstances? perhaps some deadlock issue when being driven
;; by another process or something...)
(force-output *standard-output*))
(let* ((form (funcall *repl-read-form-fun*
(results (multiple-value-list (interactive-eval form))))
(unless noprint
(dolist (result results)
(prin1 result)))))
;; If we started stepping in the debugger we want to stop now.
;;; a convenient way to get into the assembly-level debugger
(defun %halt ()
(%primitive sb!c:halt))
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